Electric dart board



March 211, 1950 J. H. HILL ELECTRIC DART BOARD Filed June 24, 1948 3Sheets-Sheet l INVENTOR: Jo/mfiarzyflzli, B) W W @MQMQ 6 A TTORN E YSMarch 23, 1950 J. H. HILL ELECTRIC DART BOARD 3 Sheets-Sheet 2 FiledJune 24, 1948 WITNESSES I /QMZWM INVENTOR Jn/z/zHar/y ATTORNEYS March21, 19 50 J. H. HILL Q 2,501,218 ELECTRIC DART BOARD 7 Filed June 24,1948 3 Sheets-Sheet 3 Z/WITNESSES .Jl lg EN 7! Z621? I {I 0 12 any 2 @fi70 W 7 y W A TTORNEYS.

Patented Mar. 21, 1950 ELECTRIC DART BOARD John Harry Hill, PennsaukenTownship, Camden County, N. J.

Application June 24, 1948, Serial No. 34,949

6 Claims.

This invention relates "to an electric indicating game board, and morespecifically relates to an electric indicating dart'boardconstructed inpart of novel replaceable segments of laminar structure.

Various indoor and outdoor target games, such as darts, archery, gunneryand the like have been made more enjoyable by providing electricindicating target areas. "In the'target, each scoring area may be wiredso that the impact of the missile or projectile on the area will cause adesignated'light to become illuminated and thus indicate visually thescoring area that the player has hit. Similarly, various horns, bells,or other audible signals may-be actuated by the impact of the missile.In games employing sharppointed missiles such as-darts, knives andarrows which pierce the surface of the target, methods have been devisedfor utilizing the -metal point and shaft of the missile to close anelectrical circult and actuatea visual or audible indicator. Forexample, targets have been constructed of layers of metallic foil orscreen separated by a layer of insulating wax such as melted paraffin orbeeswax, eachlayer of metal being connected to one terminal of theindicator.

The foregoing mechanisms have presented many difficulties anddisadvantages. The employment of an insulating wax and metallic foilshave made it necessary 'to surround each responsive or indicating areaon the target with an unwired and non-indicating area. In such devicesthe non-indicating-area is necessarily of substantial size in order tokeep the indicating area electrically separate. This has limited theapplication of theidea to-target areas of simple design, such as a smallnumber of concentric rings of which only alternate rings would respondto-the piercing action of the metal shaft and actuate the indicator. Afurther disadvantage of the methods employed in the past is thatthe'surface particles ofthe dart board. are rapidly pulverized and tornuntil one segment or local area of the entire target surface becomesworn through. This,-of-course,'renders the entire target incapable offurther use and the whole target must be discarded while only a smallarea such as the "bulls-eye is worn out. This is wasteful even inthe'case of relatively inexpensive, non-indicating dart boards. Thewaste would be greatly magnified when the board is speciallyconstructed, wired and fitted with a large number of lightsand sockets.The-use of the wax and metal-foil layers tends further to increase therate of wear by reason of plasticity,

structuralweakness, and low resistance to tear. Another disadvantage isthat systems employing metallic foil and wax have exhibited relativelypoor dart retentivity. By this I mean that when a dart is imbedded inthe layers of foil and wax, a certain amount of permanent deformationtakes place and produces a void space when the dart is removed. Asubsequently thrown dart which impinges upon the same point willsometimes not be retained in the target at all and at other times thedart will hang so loosely at the targetsurfacethat it will not providean electrical contact between the layers of metallic foil.

It is therefore one object of the present invention to provide anelectric indicating dart board with a highly durable penetratingsurface, providing a positive dart-retention. A further object is toprovide sucha dart board which doesnot contain paraffin or beeswax.

It is a further object of this invention to provide an electricindicating dart board in which individual area elements of the targetsurface may be replaced rapidly and inexpensively.

A still further object is to'provide an electric indicating'dart boardin which any point in'the entire target area willrespond to thepenetration of a dart andindicate visually or audibly which scoring areathe dart has penetrated, with no"dead or non-indicating areas on thetarget.

Still another object of-the invention is to provide an electricindicating dart board that has an indicating target-area made up oflarge numbers of adjacent scoring area segments of varying shapes andsizes, allof which are electricallyindicating.

Other objects and means for carrying them into effect will be apparentfrom the following description of the present invention and from theaccompanying drawings wherein:

Fig. l is a face viewof an embodiment of an electric indicating dartboard. 7

Fig. 2 is a sectional view on line II--1I through Fig. 1.

Fig. 3 is a fragmentary enlarged face view of the target area asindicated by the arrows III-III of'Fig.i2.

Fig. 4 is a sectional view on line IV-IV of Fig. 3.

Fig.5 is an exploded view showing the different parts oi'an innersegment. of the target'area.

Figffi is awiring diagram showing an electrical circuit that-may be usedin the embodiment of Fig. 1.

"In order to understandthe invention, reference should first be had toFig. 1 which shows the target face of a preferred form for thisinvention. While the invention obviously embodies a wide variety ofdesigns, the aforementioned specific design serves as a convenientillustrative example. Rigidly mounted in the face of the board, thereare twenty equal-sized scoring areas H which are grouped around acentral circular area or bulls-eye I2 and which are outlined by radiallines 2 intersecting a circle concentric with the central circle. Thesetriangular areas H I call the inner segments. The concentric scoringring at the outer edge of these inner segments is also divided by theradial lines into twenty scoring areas of equal size, and I call thoseareas E9 the middle segment. Similiarly, the twenty segments 9 beyondthemiddle segments are called the outer segments. Beyond the set of outersegments is a foul ring 83 which is not cut by the radial lines andwhich constitutes one undivided foul field area. Thus it may be seenthat this design contains 62 separate scoring areas, each of whichhas ascoring response independent of the others and is replaceableindependently of the others without dismantling the dart board.

In constructing the novel segments of this invention, a laminarstructure of Bakelite, wood, cork and sprayed metal is employed. It willbe understood that the bulls-eye, the inner, middle, and outer segments,and the foul field ring are of similar construction, the principaldifference in construction being merely in the size and shape of thesegment.

The various layers of which I build an inner segment are shown in Fig.5. The inner segment base 32 is made of Bakelite or the like and iscemented to the back surface of conforming wood part 3|. Two hollowcenter clamping screws 25 are firmly secured in base 32 with their headsflush with part 3| and with their threaded shafts projecting through theback of the segment. Wires 29 and 36 for connecting into the electricalcircuit hereinafter described are threaded through the hollow centers ofthe clamping screws. According to an especially convenient embodimentthe wire inside the hollow center of the clamping screw is left bare.When the hollow space within the clamping screw is filled with solder,the entire clamping screw becomes the electrical conductor and there areno loose wires to be connected. When the segment is installed in thedart board, contact clamping nuts 2i? (Fig. 4) serve as electricalconductors and as means of mechanical attachment at the same time.Mounting piece 3! is a properly-shaped wood, Celotex, or porous segment,made preferably of white pine about thick. It is provided with a holethrough which wire 29 is threaded, and a somewhat larger hole fittedwith an insulating tube 26 for wire 30. In the next step, a thin layerof cork 33, with corresponding holes for wire 29 and tube 26, isattached firmly to mounting piece 3! by cementing, gluing or the like.The strands of wire 29 are separated and distributed flat in a fanwisefashion upon the outer face of cork 33 as shown in Fig. 3. The strandsare then pressed mechanically against the face of the-cork so as toimbed the wires in the porous surface to a certain extent and to givethem a tendency to remain in place. A spray metal, of which zinc is anexcellent example and will be used for purposes of description, is thenimpinged upon the entire outer cork surface of element 33 and upon theflared strands of fine wire 29. While zinc has been used as a preferredmetal in this description, it is of course clear that many other metalssuch as copper, tin, lead, aluminum and 1611' alloys may be employed andthat various methods of metal spraying may be followed to attain asubstantially uninterrupted porous metallic contact layer. For asatisfactory method of spraying metals, reference is hereby made to theU. S. patent to Schoop, No. 1,128,058.

When the finely divided metallic spray strikes the pore-surface of thecork, the minute particles of metal distribute themselves within theirregular cavities of the corkboard pore-structure and penetrate thesurface of the cork. The metal solidifies within the interstices of theporous surface, and further quantities of metal which follow build asmooth and continuous metallic surface which is securely bonded to thecork surface and to the strands of wire 29. The zinc spray is continueduntil a substantially uninterrupted zinc layer approximately .002 inchthick is obtained. This porous layer will usually be thick enough tocover the cork smoothly while the exposed conducting wires are onlypartly covered. The zinc spray is followed by a spray of finely dividedmetallic copper to form a second porous layer having a thickness ofabout .002 inch. This layer is shown at 34 in Fig. 5 and is hereinafterreferred to as the inner metallic contact layer. On contacting the zincsurface, the hot finely divided copper spray locally melts particles ofzinc and forms a copper-zinc alloy at the interface. The interfusing andalloying of the metals joins the two metallic layers with the resultthat a tenacious metallic bond is obtained on cooling and solidifying.

Upon completion of the double metallic layer, a second cork layer 35with a single hole for insulator tube 26 is attached to the exposedcopper surface by cementing or gluing, preferably with the aid ofmechanical pressure. The second wire 30 is threaded through the hole inthe insulating tube 26. The insulating tube has the function of keepingthe two metallic layers electrically separate since in the absence ofsuch a tube, wire 30 would be likely to contact the first metal layerand short-circuit the segment.

The free ends of wire 30 at the outer surface of the segment 35 arespread fanwise and compressed against the cork. After the resultingsurface is sprayed with zinc and then with copper as before, the metalsurface hereinafter referred as the outer metallic contact layer iscovered with a third cork layer 28 which is cemented firmly and makes upthe outer surface of the segment. The construction of the layers in afinished inner segment will be seen in Figs. 3 and 4. In the innersegment I! there shown, 33 is the lower cork layer and 34 depicts themetal to cork layer after the metal spray treatment. Fine wire 29 isshown as spread out on the face of the cork and covered with the spraymetal. Fine wire 30 is spread on middle cork layer 35 which is coveredwith metal as shown at 36. Metallic layer 36 is then covered with facecork 28 and the segment is completed by affixing insulating band 31 tothe vertical surfaces as indicated in Figs. 3 and 5.

The method of operation of the dart board will now be understood. Whenthe inner metallic contact layer Wire 29 is connected through anindicating means such as a light, horn or hell to one side of a sourceof electric power such as a battery or an alternating current source andthe outer metallic contact layer wire 30 is connected directl'y'to theother terminal of the power source.

'the indi-cating means will not be energized because the two metallayers of thesegment are electrically insulated. However, whenasharppointed missile such as a knife-ora dart penetrates sufficientlyfar into the segment, it makes 'an electrical contact with layer-'36andwith layer 3], closing the electrical circuit and actuating theindicatingmeans. When the missileis removed, the circuit is opened andthe indicating'means is disconnected.

1n the foregoing manner, twenty inner segments are made up. Followingthe sameprocedure, twentymiddle segments and twenty outer segments arefabricated in appropriate shapes.

Similarly,the bulls-eye l 2'and'the foul ring 8 "are made up. Theindividual parts are then :ready to be mounted to thebase of the dartboard.

The configuration of the base of the board is of course subject to widevariation depending upon the type of game board'to be used-and the-manufacturing steps found to be most convenient and economical. Anexcellent "base of this type may be made in accordance with thedesign-shown in Fig. 2.

'Mounting board I, which is preferablymade of wood'such as white pine,is provided with suitable 'openings for light sockets and connections,and is provided with an outer moulding -2, made of hardwood. A spacerstrip 3 and a back inclosure panel 4 are included to provide space forthe electrical connections and wiring. Core base 5 is :drilled at thedesignated points for entry of the clamping screws 25 fromeach'individual segment and for their respective clamping nuts 20.

Since the position of each hole should be precise in order to insure atight fit of all segments, the

"core base should be laid-out and drilled with due erably brass.Separation at the bulls-eye is attained by means of the metallic bushingl3. These separation elements may be combined in the form of a gridwhich is fixedly mounted in board 5 by means of elements l3, l4. l5 andit which extend into board 5 as shown.

When the mechanical parts of the apparatus have been fully assembled,there remains only the relatively simple matter of connecting the unitelectrically which may be accomplished as indicated in the wiringdiagram of Fig. 6.

The electric lights which respond to the penetration of the target areamay of course be placed in any manner that is found to be desirable orpleasing to the eye. One satisfactory configuration of lights appears inFig. 1. In this configuration, it will be found desirable to make theelectrical connections in such a manner that the inner circle of lightscorresponds to the inner segments, the middle circle of lightscorresponds to the middle segments, and the outer circle of lightscorresponds to the outer segments. Special lights 2| and Zia may beprovided to denote a hit in the bulls-eye or in the foul ringrespectively and lights 22 may be used to indicate a flow of current inthe dart board circuit.

The foul field ringis similarly secured in The indicating lights thatmay be usediin connection with the game board are convenientlyconnectedasshown in Fig. 2. Light socket and bulb l8 are recessed inthemountingboardcand seatedby means of fiber bushing l. Thelights mayallbeprotected from dartlbreakage by thick transparentiLucite inserts 6.or'by .othersuitable means.

The wires projecting from the backs of the segments maybe connected inaccordance withsthe wiring diagram in Fig. 6. It will be seen thatthecompletion of each target area lighting circuit depends only upontheelectrical connection be tween the inner and outer metallic layers ofthe target face. The connection is of course supplied by's'themetallicor other electrically-conducting penetrating shaft. Sincethe lights arepreferably of theilow voltage type and the customary powertsourcecis ofahigher voltage, transformer vtil has'been included in the circuit. Ofcourse, the circuit may be a. direct-current battery circuitorotherqcircuit'if desired.

In .the practiceof this-invention, each segment must of course be keptelectrically separate from the neighboring'segments. This I haveaccomplished by'covering the side areas of each segment with athin(.003") plastic film 31 as shownin Figs. 3,-4 'and 5 using a commercialmaterial called Artus Plastic Stock which is manufactured by IndustrialProducts Suppliers, New York, New York. The insulation may otherwise beprovided by applying similarly thin coatings 'of rubber or othernon-conductors the nature 'of which will readily occur to personsskilled in the'art.

Insulation between segments may also be efiected by using non-conductingcompositions as'separator strips M, i5, i6, 24 and bushings l3. However,theedges-of any nonconductor so used will be exposed to the force ofthrown darts, and the material must therefore be capable of resistingthe 1 mechanical abrasion and penetrating and tearing forces exerted bythe darts.

The specific metal contact layer made up'of a double spray of zinc andcopper as above tie-.-v scribed is particularly effective and durable.'The zinc coat forms a tenacious adhesive bond with the cork, while thecopper layer is an excellent electrical contact surface and contributesmaterially to the flexibility and strength of the metallic layer and tothe strength of the entire penetrated surface. As contrasted with aplain corkboard or a board containing layers of metal foil, the productof this invention has the property of excellent dart retentivity. Thepresence of the layers of sprayed metal provides a substantially stablepenetrating base for trapping the metal shaft of the missile and holdingit in position. The adaptation of the metal to the porous structure ofthe adjacent cork produces a yielding and flexible penetrating surfacewhich suffers little permanent deformation on being penetrated by adart, and which has excellent wear-resisting qualities. The provision ofsprayed metal layers F affords a compact, coherent segment that holdsits shape even better than plain corkboard, thus allowing theconstruction and use of replaceable segments.

It is clear that the use of a replaceable segment made of materials thatdeform after hard usage would be fruitless; yet without the feature ofreplaceable segments the rapid wear of a few local areas of the boardwould require premature discard of the board and would make the cost ofreplacement prohibitive.

I claim:

1. A replaceable dart board segment comprising an inner layer of cork,an inner metal stranded wire the strands of which are distributedagainst the surface of said cork, an inner metallic layer made up of apreliminary zinc layer conforming to the irregularities of the cork andthe wire strands and a subsequent layer of copper bonded to the zinclayer, a middle cork layer, an outer metal stranded wire the strands ofwhich are distributed against the surface of the middle cork, an outermetallic layer made up of a preliminary zinc layer conforming to theirregularities of the cork and the wire strands and a subsequent layerof copper bonded to the zinc layer.

2. In an electric dart board a base member and a plurality ofelectrically insulated, unitary, replaceable segments removablyconnected thereto, each of said unitary segments comprising, in fixedrelation, a segment base, a dart receiving element affixed to saidsegment base, a non-conductive, porous layer attached to said dartreceiving element, an inner metallic contact layer integral with andconforming to the irregularities of said porous layer, a middle porouslayer overlying said inner metallic contact layer, and an outer metalliccontact layer affixed to the upper surface of said middle layer, thepores of said porous layers being substantially penetrated by themetallic contact layers.

3. In an electric dart board the combination of a base member and aplurality of the segments of claim 1 removably attached thereto.

4. A unitary replaceable dart board segment comprising an inner layer ofa porous, non-conductor of electricity, an inner stranded electricalconductor the strands of which are distributed against the face of saidporous inner layer, an inner porous metallic layer bonded to said porousnon-conductor and conforming to the irregularities thereof andconforming to the irregularities of the strands, a middle layer of aporous nonconductor of electricity, an outer stranded electricalconductor the strands of which are distributed against the face of saidporous middle layer, and an outer porous metallic layer bonded to themiddle porous non-conductive layer and conforming to the irregularitiesof the inner porous layer and conforming to the irregularities of thestrands.

5. A unitary replaceable dart board segment comprising a segment baseand a series of alternate layers of electrical insulators and electricalconductors, all of said layers and the segment base being attachedtogether to form a stable unit, one of said electrical insulators beinga porous material and one of said electrical conductors being a porousmetal bonded by penetration to said porous material. r

6. In an electric dart board, a unitary replace able segment comprisinga segment base, a porous surfaced cork layer affixed to said segmentbase, a sprayed metal layer adhering to and penetrating theirregularities of the cork surface of said cork layer, an electricallynon-conductive layer on said sprayed metal layer, an electricallyconductive layer on said electrically non-conductive layer, anelectrical conductor connected to said sprayed metal layer and anotherelectrical conductor connected to said electrically conductive layer,each of said conductors passing through said segment base, whereby aconductive missile penetrating the sprayed metal layer and theelectrieally conductive layer connects said conductors electrically. I

JOHN HARRY HILL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,057,677 Shaw Apr. 1, 19131,164,008 Moore Dec. 14, 1915 2,168,644 Browning Oct. 14, 1936 2,330,202Brennan Sept. 28, 1943 FOREIGN PATENTS Number Country Date 439,172 GreatBritain Nov. 26, 1935

